Method of forming a drive fastener device

ABSTRACT

The present disclosure relates generally to improvements in staples and spikes and in methods for producing the same. The work engaging extremities of the staple or spike tines are formed with oppositely disposed converging swaged surfaces. Each tine extremity also present opposed longitudinal surfaces disposed at substantially 90* with respect to the converging swage surfaces, and terminate at opposite ends of a complemental arcuate or curved work engaging edge. The invention also contemplates a novel method of producing the above-mentioned structure by shearing and swaging the opposite extremities of a pre-determined length of metallic rod stock.

United States Patent [191 Larson [111 3,811,269 [451 May21, 1974 METHOD OF FORMING A DRIVE FASTENER DEVICE [75] lnventor: Charles 0. Larson, Sterling, Ill. 73 Assignee: Chas. 0. Larson Co., Sterling, m.

[22] Filed:

Sept. 11, 1972 [21] Appl. No.: 288,055

Related US. Application Data [62] Division of Ser. No. 46,397, June 15, 1970,

FOREIGN PATENTS OR APPLICATIONS 9,961 6/l902 Great Britain 85/30 Primary Examiner-Charles W. Lanham Assistant Examiner-Gene P. Crosby Attorney, Agent, or Firm-Olson, Trexler, Wolters,

Bushnell & Fosse, Ltd.

[57] ABSTRACT The present disclosure relates generally to improvements in staples and spikes and in methods for pro-.

ducing the same. The work engaging extremities of the staple or spike tines are formed with oppositely disposed converging swaged surfaces. Each tine extrems l elsqprs 912129 91 o itudinalsu is se at substantiall 90 with respect to the conv'ging swage surfaces, and terminate at opposite ends of a complemental arcuate or curved work engaging edge.

The invention also contemplates a novel method of producing the above-mentioned structure by shearing and swaging the opposite extremities of a predetermined length of metallic rod stock.

8 Claims, 22 Drawing Figures PATENTEMm m4 3131 1.269 sum 1 'or 3 PATENTEDme: m4 3811.269

' sum 2 or a PATENTEMY 2 1 I974 SHEET 3 [IF 3 METHOD OF FORMING A DRIVE FASTENER DEVICE REFERENCE TO RELATED APPLICATION- This application'is a division of US. application Ser. No. 46,397, filed June 15, 1970, now abandoned.

SUMMARY OF THE INVENTION It is a well-known fact that many of the staple and spike devices now available on the open market have structural deficiencies which render such devices difficult to properly drive in place. One of such deficiencies results from mis-alignment of the entering or work engaging extremities thereof. Such mis-alignment has a tendency to cause the tine to tilt or cant when hammerdriven into a workpiece. Also in attempting to drive a staple or spike having blunt or mis-shaped tine extremities into a workpiece there exists the potential hazard of cracking the work, and this is particularly evident in instances where the workpiece consists of a section of conventionally grained wood.

It is therefore one of the important objects of the present invention to provide novel staples and spikes which may be produced at minimum cost and which will present uniformity in structural excellence and thus avoid the disadvantages referred to above.

More specifically, the present invention contemplates the production of the above mentioned fastener devices having such structural uniformity and correctness at the point of initial penetration within a workpiece that the possibility of tilting or canting, as well as cracking of the workpiece, is reduced to a minimum.

To assure the aforesaid uniformity and correctness in structural design, the present invention also contemplates improved, practical methods of producing such staples by practicing novel shearing and swaging steps, resulting in the formation of accurately positioned, curved chisel-like edge at the free extremity of each staple tine.

BRIEF DESCRIPTION OF THE DRAWINGS of predetermined length sheared from the rod material of FIG. I;

FIG. 3 is an elevational view or the predetermined length of rod stock of FIG. 2, formed with oppositely disposed swaged surfaces converging into a chisel-like curved or arcuate edge. The swaging operation may occur before or after the predetermined length of stock of FIG. 2, has been bent into'U-shape, and this U-shape form is illustrated by dotted lines in FIG. 3;

FIG. 4 is a side elevational view of the U-shaped staple after initial swaging, dotted lines indicating ultimate shape of the staple tines;

FIG. 5 is an enlarged illustration of the swaged side of one of the stapled tines as viewed in FIG. 4, with dotted lines indicating the opposite elongated sections of the swaged sides which have been removed as for example by shearing; I

FIG. 6 is a view similar to FIG. 5, more clearly to il- Iustrate the curved or arcuate chisel-like edge formed by the converging swaged sides of the tines;

FIG. 7 is a side elevational view similar to FIG. 4, after opposed sections of the swaged surfaces have been removed so as to provide converging side surfaces disposed at substantially with respect to the previously swaged surfaces;

FIG. 8 is an enlarged fragmentary elevational view of the staple tine as viewed from the right of FIG. 7;

FIG. 9 discloses a predetermined length of metallic rod material in association with swaging dies employed to impart a substantially semi-spherical shape to each end of the rod;

FIG. 10 discloses the metallic rod of FIG. 9, bent into U-shape;

FIG. 11 discloses the U-shaped member of FIG. 10 swaged on opposite sides of each staple tine to provide surfaces which converge to provide chisel-like curved edges;

FIG. 12 is a diagrammatic illustration of the manner in which swaging dies may be employed to swage the opposite sides of the staple tines;

FIG. 13 discloses one of thestaple tines in association with shearing dies employed to remove opposite elongated sections of the previously swaged surfaces;

FIG. 14 is a perspective view of the arrangement shown in'FIG. 13, more clearly to illustrate the opposite elongate sections sheared from each staple leg or tine;

FIG. 15 is a perspective view of a staple type fastener before the opposite extremities thereof have been swaged;

FIG. 16 is an elevational view of the staple device of FIG. 15, after opposite sides of the tines thereof have been acted upon by swaging dies; I

FIG. 17 is a vertical, sectional view taken substantially along the line l7--17 of FIG. 16, the staple tine being shown in elevation;

FIG. 18 is a view similar to FIG. 16, disclosing the FIG. 19 is a detailed fragmentary perspective view of one of the tines, more clearly to illustrate the chisel-like shape of the work engaging extremity of a tine;

FIG. 20 is a perspective view of a spike device having the entering extremity thereof shaped to conform with the entering extremities of the staple device shown in FIG. 15;

FIG. 21 discloses the spike device of FIG. 20, after opposite sides of the entering portion thereof have been subjected to swaging dies; and,

FIG. 22 is a vertical sectional view taken substantially along the line 22-22 of FIG. 1, the spike being shown in elevation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings more in detail wherein like numerals have been employed to designate similar parts throughout the various figures, it will be seen that one embodiment of a staple constructed in accordance with 1 the teachings of the present invention is designated generally by the numeral 16 in FIG. 7. The staple 16 comprises a bight portion 18 and parallel tines 20. The extremities of the tines are indicated generally by the numeral 22. I

In the production of the staple 16 a predetermined or given section of metallic rod material is severed from the length of the stock shown in FIG. 1. This severance results from shearing the stock in a direction substantially normal to the rod or stock axis. The opposite extremities of thesevered length or section of rod stock may now be swaged by the application of suitable swaging dies to the opposite sides of the rod extremities. This swaging operation may occur before or after the severed stock has been formed into a U-shape as illustrated by the dotted lines in FIG. 3, and as shown by the solid lines in FIG. 4. It is of importance to note that the swaging operation is such as to produce a-discreet curvature or arcuate shape in a chisel-like edge 24, at the extremity of each tine 22. Thus, by swaging opposed sides of each of the tine extremities converging side surfaces of each tine terminate in the aforesaid chisellike arcuate work engaging edges 24.

After the above-mentioned swaging operation is completed, opposite longitudinal peripheral sections 26 of each tine may be removed or separated from the remainder of the tinebody as for example by employing suitable shearing dies. In FIG. 4, these longitudinal peripheral sections 26 are disclosed before severance, and in FIG. 7, the completed staple illustrates the shape of the staple tines after the sections 26 have been sheared from the central tine body. It will be'noted that v removal of the oppositely disposed longitudinal peripheral sections 26 provides a pair of oppositely disposed converging surfaces 28, disposed at substantially 90 with respect to the above-mentioned swaged surfaces In fact, thefconverging extremities of the surfaces 28 terminate at opposite ends of the curved chisel-like edges 24. In other words, the planes coincident with the surfaces 28 intersect the cu'rved'or arcuate chisel-like edges. This resulting curved edge of limited extent greatly facilitates the ease with which the completed staple may be driven into a workpiece.

From the foregoing it will be apparent that a staple device constructed in accordance with the teachings of the present invention provides swaged opposed sides of each tinewhich converge into chisel-like arcuate or curved w'ork entering edges of limited extent, positioned within a common plane coincident with the plane which includes a central longitudinal axes of the staple tines. This plane is indicated by the dot and dash line 30, of FIG. 8. Also the oppositely disposed surfaces 28 converge toward a central longitudinal plane designated by thedot and dash line 32 in FIGS. 5, 6 and 7. The uniform convergence of the swaged surfaces toward the central plane 30, and the uniformity in convergence of the longitudinal. opposed surfaces 28 toward the central planes 32, together withthe provision of the curved or arcuate chisel-like edge 24 of limited extent reduces to aminimum the tendency for the staple to tilt or cant when driven into a workpiece. Also the tendency for a workpiece to crack or split is substantially eliminated.

In FIGS. 9-14 inclusive, a slightly modified method of producing applicant's improved staples is shown. The only significant difference in this method from the previously described method is in forming, asby swagpiece. I

in FIG. 9, the opposite extremities of the rod section of given length is shown in association witli suitable swaging dies 34, which when applied to the opposite extremities of the rod will form rod extremities 36 which are arcuate or curved in longitudinal section.

The staple structure of FIGS. 10 to 14 inclusive, designated generally by the numeral 16a, has a bight portion 18a, and leg or tine portions 20a. Structural features of the staple 16a, corresponding with previously described structural details are indicated by similar numerals bearing the suffix a. FIG. 12 discloses a pair of swaging dies 38 which may be employed to swagc opposite longitudinal sides of the staple tines to form the chisel-like edges 24a, and in FIG. 13, a pair of dies 40 are shown which may be employed to shear oppositely disposed longitudinal sections 26d and thus provide each tine with a pair of converging surfaces 28a, terminating at opposite extremities of the curved chisel-like edge 24a of limited extent. By forming curved tine extremities before lateral swaging thereof, a more pronounced or distinct curvature of the work engaging edge is assured. Thus thediscreet chisel-like curved work engaging edges greatly facilitate the ease with which the fastener tines may be driven into a work- In FIGS. 15-19 inclusive, a still further modified form of fastening device is disclosed representing another embodiment contemplated by the present invention. FIG. 15 discloses a partially formed drive fastener or staple similar to structures shown in F IG. 10. The device of FIG. 15', is designated generally by the numeral 16b. This structure includes a bight portion 18b, and a pair of spaced tine portions or sections 201) having tip portions 3617. FIG. 16 discloses the device 16b after s'waging dies 3812 have been applied to the opposite sides of the enterin'g'e'xtremities 22b of the tines 20b. Note that this results in the formation of curved or arcuate chisel-like edges 2412 similar to the previously described cur-ved work engaging edges 24a.

Referring now to FIG. 18, it will be seen that suitable shearing dies 40!) may be employed to shear or cut away oppositely disposed elongate side sections 26b of each tine extremity 22b. In so doing oppositely disposed spurs or locking protuberances 42 are formed.

Thus the drive fastener device 16b is not only provided with curved chisel-like entering-edges 24b, but also with the locking spurs 42 which serve to increase resistance to forces tending to withdraw the fastener from the workpiece into which it has been driven.

A still further modified fastening device contemplated by the present-invention is disclosed in FIGS. 20-22 inclusive. This fastener is in the form of a spike designated generally by the numeral 16c. This spike has a body portion 20c and an entering section 22c. The entering tip 36c of the spike 16c is formed or swaged similarly to the previously described entering curved tips 36b of the staple device 16b. The entering extremity of the spike 160 is swaged and sheared in a manner similar to the previously described method of forming the chisel-like edges and spurs 42. Structural details of the spike 16c corresponding with the previously described structure in FIGS. 15-19 inclusive, are

' given corresponding numerals bearing the suffix c. It

ing, the extremities of the predetermined length of rod will suffice to say the spike 16c incorporates a curved or arcuate chisel-like work engaging edge 240 as well as locking spurs 42c. Dies 380 function to swage opposite sides of the entering extremity of the spike, and

dies 40c function to shear away oppositely disposed elongate sections 26c. v

From the foregoing it will be apparent that in practicing the novel and practical methods contemplated by the present invention, the cost of producing structurally uniform staples and spikes of the aforesaid novel design is greatly reduced. Also the fastener structures resulting from the practice of such methods are greatly improved over many of the fasteners now available on the open market. Each tine is provided with chisel-like arcuate work engaging edges of limited extent positioned within a common plane coincident with the plane which includes a central longitudinal axes of the staple tines. By swaging the opposite sides of the tines to form the chisel-like cutting edge along the line of intersection of such surfaces, the hardness and toughness of the material of the tines is materially enhanced. The provision of the oppositely disposed locking spurs materially increasesthe resistance to forces tending to loosen the fastener.

I claim:

1. The method of forming drive fasteners from metallic rod stock including the steps of, separating a section of predetermined length from said stock by shearing in a direction substantially normal to the rod axis, and swaging opposed sides of at least one extremity of said severed length so-as to present a tine having converging side surfaces terminating in a chisel-like arcuate work engaging edge positioned within a common plane coincident with the plane which includes the central longitudinal axes of said tine, and removing opposite longitudinal peripheral sections of the swaged tine to present opposed longitudinal surfaces disposed at substantially 90 with respect to said converging swaged surfaces and terminating in the vicinity of the opposite ends of the arcuate work engaging edge.

2. The method of forming drive fasteners from metallic rod stock including the steps, of separating a section of predetermined length from said stock by shearing in a direction substantially normal to the rod axis, and swaging opposed sides of at least one extremity of said severed length so as to present a tine having converging side surfaces terminating in a chisel-like arcuate work engaging edge positioned within a'common plane coincident with the plane which includes the central longitudinal axes of said tine, and removing opposite longitudinal peripheral sections of the swaged tine to present opposed longitudinal converging surfaces disposed atsubstantially 90 with respect to said converging swaged surfaces and terminating in the vicinityof the opposite ends of the arcuate work engaging edge.

3. The method of forming drive fasteners from metallic rod stock including the steps of, separating a section of predetermined length from said stock by shearing in a direction substantially normal to the rod axis, shaping an end of the severed length so as to present a rounded tine end surface, swaging opposite sides of said tine extremity to form converging side surfaces terminating in a chisel-like arcuate work engaging edge positioned within a common plane coincident with the plane which includes the central longitudinal axes of said tine, and removing opposite longitudinal peripheral sections of said swaged tine to present opposed longitudinal surfaces disposed at substantially 90 with respect to said converging swaged surfaces'and terminating in the vicinity of the opposite ends of the arcuate work en- 6 gaging edge.

4. The method of forming drive fasteners from metallic rod stock including the step of severing a section of pre-determined length from said stock, forming an end of the severed length so as to present a rounded tine end surface, and swaging opposed sides of the extremity of said severed length having the rounded end surface so as to present a tine having converging side surfaces terminating in a chisel-like arcuate work engaging edge positioned within a common plane coincident with the plane which includes the central longitudinal axes of said tine.

5. The method of forming drive fasteners from metallic rod stock as set forth in claim 4, which includes the step of removing opposite longitudinal peripheral sections of the swaged tine to present opposed longitudinal surfaces disposed at substantially with respect to said converging swaged surfaces and terminating in the vicinity of the opposite ends of the arcuate work engaging edge.

6. The method of forming drive fasteners from metallic rod stock as set forth in claim 4, which includes the step of so removing opposite longitudinal peripheral sections of the swaged tine to present opposed longitudinal surfaces disposed at substantially 90 with respect to said converging swaged surfaces and terminating in the form of locking spurs in the vicinity of the opposite ends of the arcuate work engaging edge. 1

7. The method of forming staples from metallic rod stock including steps of, separating a section of predetermined length from said stock by shearing in a direction substantially normal to the rod axis, and applying pressure to opposed extremities of the severed length to form a staple loop, and swaging opposed sides of each of said extremities so as to present a pair of tines having converging side surfaces terminating in chisellike arcuate work entering edges oflimited extent positioned within a common plane coincident with the plane which includes the central longitudinal axes of the staple tines, and removing opposite longitudinal -peripheral sections of each swaged staple tine to present opposed longitudinal converging surfaces disposed at substantially 90 with respect to said converging swaged surfaces and terminating at opposite ends of a complemental arcuate work engaging edge. 1

8. The method of forming staples from metallic rod stock includingthe step of separating a section of predetermined length from said stock by'shearing in a direction substantially normal to the rod axis, and applying pressure to opposed extremities of the severed length to form a staple loop, shaping the end surfaces of said staple loop so as to present rounded tine end surfaces, swaging opposite sides of each staple extremity to form converging side surfaces terminating in chisel-like arcuate work entering edges of limited extent positioned within a common plane coincident with the plane which includes the central longitudinal axes of the staple tines, and removing opposite longitudinal peripheral sections of each swaged staple tine to present opposed longitudinal converging surfaces disposed at substantially 90 with respect to said converging swaged surfaces and terminating in the vicinity of the opposite ends of a complemental arcuate work engaging edge. 

1. The method of forming drive fasteners from metallic rod stock including the steps of, sepArating a section of predetermined length from said stock by shearing in a direction substantially normal to the rod axis, and swaging opposed sides of at least one extremity of said severed length so as to present a tine having converging side surfaces terminating in a chisel-like arcuate work engaging edge positioned within a common plane coincident with the plane which includes the central longitudinal axes of said tine, and removing opposite longitudinal peripheral sections of the swaged tine to present opposed longitudinal surfaces disposed at substantially 90* with respect to said converging swaged surfaces and terminating in the vicinity of the opposite ends of the arcuate work engaging edge.
 2. The method of forming drive fasteners from metallic rod stock including the steps, of separating a section of predetermined length from said stock by shearing in a direction substantially normal to the rod axis, and swaging opposed sides of at least one extremity of said severed length so as to present a tine having converging side surfaces terminating in a chisel-like arcuate work engaging edge positioned within a common plane coincident with the plane which includes the central longitudinal axes of said tine, and removing opposite longitudinal peripheral sections of the swaged tine to present opposed longitudinal converging surfaces disposed at substantially 90* with respect to said converging swaged surfaces and terminating in the vicinity of the opposite ends of the arcuate work engaging edge.
 3. The method of forming drive fasteners from metallic rod stock including the steps of, separating a section of predetermined length from said stock by shearing in a direction substantially normal to the rod axis, shaping an end of the severed length so as to present a rounded tine end surface, swaging opposite sides of said tine extremity to form converging side surfaces terminating in a chisel-like arcuate work engaging edge positioned within a common plane coincident with the plane which includes the central longitudinal axes of said tine, and removing opposite longitudinal peripheral sections of said swaged tine to present opposed longitudinal surfaces disposed at substantially 90* with respect to said converging swaged surfaces and terminating in the vicinity of the opposite ends of the arcuate work engaging edge.
 4. The method of forming drive fasteners from metallic rod stock including the step of severing a section of pre-determined length from said stock, forming an end of the severed length so as to present a rounded tine end surface, and swaging opposed sides of the extremity of said severed length having the rounded end surface so as to present a tine having converging side surfaces terminating in a chisel-like arcuate work engaging edge positioned within a common plane coincident with the plane which includes the central longitudinal axes of said tine.
 5. The method of forming drive fasteners from metallic rod stock as set forth in claim 4, which includes the step of removing opposite longitudinal peripheral sections of the swaged tine to present opposed longitudinal surfaces disposed at substantially 90* with respect to said converging swaged surfaces and terminating in the vicinity of the opposite ends of the arcuate work engaging edge.
 6. The method of forming drive fasteners from metallic rod stock as set forth in claim 4, which includes the step of so removing opposite longitudinal peripheral sections of the swaged tine to present opposed longitudinal surfaces disposed at substantially 90* with respect to said converging swaged surfaces and terminating in the form of locking spurs in the vicinity of the opposite ends of the arcuate work engaging edge.
 7. The method of forming staples from metallic rod stock including steps of, separating a section of predetermined length from said stock by shearing in a direction substantially normal to the rod axis, and applying pressure to opposed extremitieS of the severed length to form a staple loop, and swaging opposed sides of each of said extremities so as to present a pair of tines having converging side surfaces terminating in chisel-like arcuate work entering edges of limited extent positioned within a common plane coincident with the plane which includes the central longitudinal axes of the staple tines, and removing opposite longitudinal peripheral sections of each swaged staple tine to present opposed longitudinal converging surfaces disposed at substantially 90* with respect to said converging swaged surfaces and terminating at opposite ends of a complemental arcuate work engaging edge.
 8. The method of forming staples from metallic rod stock including the step of separating a section of predetermined length from said stock by shearing in a direction substantially normal to the rod axis, and applying pressure to opposed extremities of the severed length to form a staple loop, shaping the end surfaces of said staple loop so as to present rounded tine end surfaces, swaging opposite sides of each staple extremity to form converging side surfaces terminating in chisel-like arcuate work entering edges of limited extent positioned within a common plane coincident with the plane which includes the central longitudinal axes of the staple tines, and removing opposite longitudinal peripheral sections of each swaged staple tine to present opposed longitudinal converging surfaces disposed at substantially 90* with respect to said converging swaged surfaces and terminating in the vicinity of the opposite ends of a complemental arcuate work engaging edge. 